Recovery of residual fertilizer nitrogen by canola in awintercanola-forage maizerotation

Fertilizer N residual use in agriculture is recognized worldwide as an alternative fertilizer and to a sharpdecreaseof the nitrate concentration in seepage water recharging the groundwater. In order to evaluate recoveryof residual fertilizer-nitrogen by canola in a canola-forage maize agroecosystem, a field experiment wasconductedat research farm of Shahrekord University, 2008-2009. Experimental design was a randomized complete block with four replicates. Treatments include residues of 0, 100, 200 and 300 kg N ha-' in the form of urea and broiler litter which that this soil amendments were applied in spring for maize as prior crop.Canola was planted in mid­September following forage maize harvest. The results showed that broi ler N residual increased pod/plant,seed/pod,1000seed weight, grainyield, dary matter, oil concentration and oil yield compared with the Nresidual of urea. The greatest pod/plant, I 000 seed weight, grain yield, oi l concentration and oil yield were obtained with 300 kg N ha-' from source of poultry litter, but 200 kg N ·ha-' from broiler l itter produced theh ighest seed/pod and biological yield. In conclusion, utilization N residual after maize harvest wou ld helptomin i mize the use of high cost synthetic mineral fertil izers for canola production and represents an environmentally and agronomically sound management strategy.